Circuit control



March 1, 1949. SHERWOOD 2,463,470

CIRCUIT cou'rnoL I I Filed Nov. 1, 1946 ZSnoentor Henry A. Sherwood,

Patented Mar. 1, 1949 CIRCUIT CONTROL Henry A. Sherwood, New York, N. Y., assignor to Waldes Koh-I-Noor, Inc., a corporation of New York Application November 1, 1946, Serial No. 707,125

9 Claims.

This invention relates to time limit relay electrical controlling devices by means of which a sequence of operations may be accomplished for controlling power-consuming circuits in various ways.

The invention has other uses, but is especially adapted for use in connection with petroleum engines such as may be used on automobiles, trucks and the like whether the engines are of the usual ignition type or Diesel engines. It contemplates a circuit for starting the. operation of the engine which initiates a second circuit for maintaining the operation of the engine in which second circuit may be a switch which causes it to be deenergized after a time interval, unless the operation of the engine produces suflicient pressure in the oil lubricating system.

In the enclosed drawing is shown a circuit diagram of one means for carrying out the invention.

The usual storage battery l may be used as a source of electrical energy or, when the engine is running, energy may be taken from the automobile generator indicated at 2. Both are grounded on one side and both are connected at their other sides to the wire 3. A starting switch 4 may be employed to initiate action of the system. A short closure of switch 4 energizes the starter 5 to start the motor turning in the usual way. Current also flows through the switch 4 from the wire 3 through a coil 6 about a core 1 of a relay 8. This causes the armature -9 to be attracted, closing the switch 10 so that current may flow from the wire 3 through the switch It! and the armature 9 to the point ll, whence one branch goes through the switches l2 and I3, through a heating coil l4, about a bimetallic thermal device [5, so arranged that when it becomes heated it bends to the right and pushes to the right the switch operating element I6 (which latter is biased to the left by spring 32), on which is mounted the connecting bar I! for the switches l2 and I3, thus opening the circuit at l2, 13. Another path of current from the point ll goes through the limiting resistor l8 to the point Hi from which one branch goes to ground through the holding coil 20 of the relay 8. From l9 another branch goes through the contacts 2! and 22. These are closed by the connecting bar I! when the switch operating element [6 has been moved to the right as the thermal element i5 is heated. The contact 22 is connected through the bimetallic element l5 and the switch 23 which is normally closed but opened by movement of the element [5 when it becomes heated; From 23 current may flow to ground through the wire 24 and the contacts 25 and 26 of a pressure switch 21 attached to the lubricating oil system 28, so that when the oil pressure rises as the motor operates, it forces the connecting member 29 to the left to break contact between 25 and 26. From the point another wire 30 may run to the ignition device of an explosion engine, not shown, or to an oil control valve 3| to open and let through a flow of fuel oil to a Diesel engine. The circuit of wire 30 may be referred to as the working circuit or the supervised circuit. Also connected to the wire 30 may be the various service devices of an automobile such as the lights 35, or heater 35, and also windshield wiper, defroster, radio and the like,

which are not shown.

When at rest, the apparatus will be in the position shown. On closing the starter switch 4 for a short time, the engine will turn over and the coil 6 will be energized, attracting the armature 9, closing the contact III to open the valve 3| or to feed current to the ignition system, and thus start the motor operating. At the same time, the closure of switch ID will energize the coil 20 and the switch [0 will be held closed as long as the coil 20 is sufliciently energized so the starter switch 4 may be released or opened. On the closure of H), the coil [4 will be energized through l2 and I3. As the coil l4 heats up it bends the bimetallic element 15 to the right, pushing switch operating element IE to the right. This movement causes the bridging or connecting bar I! to open the contacts l2 and I3 and close the contacts 2! and 22. This opens the circuit through coil l4 and the member l5 on cooling returns to its original position to close switch 23. There is thus closed a circuit from point l9 through 2|, 22 and 23 through pressure switch 21. If oil pressure has been built up the circuit is open at 25 and 26, but if pressure has not been built up this circuit remains closed, and there is thus formed a short circuit around the coil 20 which thus receives insufficient current to keep the armature 9 attracted and allows the spring 32 to pull the armature 9 to open the switch 10 and return the apparatus to open or deenergized position.

When the ignition switch of an explosion engine is turned off, the oil pressure goes down at once, closing the switch 21 to return the apparatus to original position. A Diesel engine, however, dies more slowly and the oil pressure may remain high enough to delay the closure of the switch 27 and it may be desirable to provide" an additional switch such as 34 connected to the point l9. This switch 34 is normally open but may be closed for a short period to provide a short circuit to deenergize the coil 20 and so return the apparatus to original inoperative position, although there may be sufiicient residual oil pressure to hold the switch 21 open for a short time.

While the relay coil 20 is energized, the operating circuit through 3|, or the ignition circuit, is closed and the coil will remain energized, while the thermal coil l4 heats up and moves the connecting bar l1 to the right to open the circuit of said coil l4, whereupon the coil cools. When the coil l4 cools, it will deenergize 20 by short circuiting it through the pressure switch 21. If, however, during this interval the pressure has built up so as to open the switch at 29, the short circuit will be opened and the coil 20 will remain energized and current will continue to flow to theoperating circuit through 3| or the ignition circuit. The time interval of this delayed action may depend upon the ccnstruction, arrangement or adjustment of the thermally operating device.

For emergency or other use, there may be provided a manual switch 33 short'circuiting. the switch l and feeding current directly to the controlled devices such as 3| or the ignition, etc., not shown.

Since the controlled circuits for fan, lights, etc. are indicated as connected through I0, the arrangement may prevent the drain of the battery current when the motor is not operating, if by inadvertence the individual control switches have not been turned off.

The oil pressure system neednot be physically combined in the same housing as the rest of the apparatus. It may be sufiicient to assemble that part of the apparatus enclosed by the frame 31 in any suitable place to be connected by wire or cable with the remaining devices, wherever they may be placed conveniently.

I claim as my invention:

1. Time-delay electrical controlling means, comprising a first circuit, a relay energized upon closing of said circuit, a second circuit energized responsively to energization of the relay, a third circuit including normally open first and normally closed pressure responsive switch means, a thermal delay-action device operative upon energization of said second circuit to open said second circuit a predetermined time interval after its energization and thereupon to close said first switch means of said third circuit, said pressure responsive switch means opening in response to a predetermined pressure condition but remaining closed in the absence of such condition to provide for closing of said third circuit upon closing of said first switch means, said third circuit when closed being operative to effect deenergization of the relay.

2. Time-delay electrical controlling means as set forth in claim 1, wherein said second and third circuits are branch circuits connected in parallel with the first circuit.

3. Time-delay electrical controlling means as set forth in claim 1, wherein a relay holding circuit energized responsively to energization of the second circuit is connected in parallel therewith, and wherein said third circuit is connected in shunt relationship to the relay holding circuit and is operative when closed to effect short-circuiting of said relay holding circuit.

4. Time-delay electrical controlling means, comprising a first circuit connected to a source of electrical energy, means for momentarily closing said st circuit, a relay adapted to be energized upon closing of said first circuit, a holding circuit for the relay, a second circuit connected in parallel to said first circuit, said holding circuit being operative to maintain the relay energized and thereby the second circuit closed following opening of the first circuit, a thirdcircuit including a normally open first and a normally closed pressure responsive switch means, said third circuit being connected in parallel to the second and relay holding circuits, a thermal delay-action device operative upon energization of the second circuit to open said second circuit a predetermined time interval aiter its energization and thereupon to close said first switch means of said third circuit, said pressure responsive switch means opening in response to a predetermined pressure condition but remaining closed in the absence of such condition to provide for closing of said third circuit upon closing of said first switch means, said third circuit when closed being operative to short-circuit the relay holding circuit.

5. Time-de1ay electrical controlling means as set forth in claim 1, wherein said thermal delayaction device includes a thermally responsive member, a heating coil in said second circuit for heating said member, and a switch operating element movable in one direction only by said member upon heating thereof and in the opposite only upon deenergization of said relay.

6. Time-delay electrical controlling means, as set forth in claim 1, wherein normally closed v switch means are provided in said second circuit,

and wherein said thermal delay-action device includes a thermally responsive member, a heating coil in said second circuit, and a switch-operating element movable by said member upon heating thereof in one direction to open said normally closed switch means and in the opposite direction upon deenergization of the relay.

7. Time-delay electrical controlling means as set forth in claim 1, wherein said thermal delayaction device includes a thermally responsive element connected in said third circuit and adapted to complete said circuit when cool, and a heating coil connected in said second circuit for heating said thermally responsive element.

8. In a switching device, a first circuit, a relay energized upon closing of said circuit, a supervised circuit energized upon energization of the relay, thermal delayed-action means operative upon energization of the relay to maintain said supervised circuit closed throughout a cycle of heating and cooling, and a supervisory circuit connected in parallel to said supervised circuit and including a normally closed pressure-responsive switch means opening only in response to a predetermined pressure condition, said supervisory circuit being conditioned for closing upon the completion of said cycle and being closed upon the pressure responsive switch means remaining closed, thereby to efi'ect deenergization of the relay and consequent opening of the supervised circuit.

9. In a switching device, a source of electrical energy, a first circuit, means for momentarily energizing said first circuit from said source, a 'relay initially energized upon energization of the first circuit. a supervised circuit connected to said source through said relay and in parallel to said first circuit, a relay holding circuit connected in parallel to said supervised circuit and operative to maintain the relay energized following opening of the first circuit, thermal delay-action means operative upon energization of the relay to inaintalin tgiehsuigfilrviseddcircifit closed} throushm-zrmmzcas crmn on a cyc e o ea 3 an coo ng, an a supervisory circuit connected in parallel to said superfi sla fi are of m the vised and relay holding circuits and adapted e 0 en when closed to short-circuit the relay holding cir UNITED STATES PATENTS cult and thereby eflect deenergization of the relay, said supervisory circuit including normally i figg zz gf fi closed pressure-responsive switch means opening 1'821853 short 1931 only in response to a predetermined pressure con- 1'854868 -g 1932 dition, said supervisory circuit being conditioned to; 2166'498 L July 1 1 3 for closing upon completion of said cycle and be- 2242'772 Bale: May 1941 ins closed through the pressure-responsive switch 2376664 Crise Ma 1945 means upon the latter remaining closed. "r y HENRY A. SHERWOOD. 

